This invention relates to polypropylene compositions; more particularly, the invention relates to the use of specified processing aids in talc filled polypropylene compositions. Polypropylene is a well known and widely used polyolefin. Polypropylene can be processed by methods common to thermoplastics. Various fillers including talc can be used in polypropylene compositions.
Talc is particularly preferred because it is readily available at low cost. Its inertness makes it an excellent extender with very little sacrifice to the polymer's physical properties. Additionally, talc increases the polypropylene stiffness, impact resistance and strength.
However, the addition of talc to polypropylene affects various properties including surface appearance and the flow of the molten composition. The melt flow rate of the composition is important because it relates to the length of molding cycles. Additional properties of talc filled polypropylene composition which are of concern are the impact resistance and the affect of heat as measured by the heat deflection temperature (HDT) which is also known as the heat distortion temperature.